No other single school has developed such spectacular and arcane rituals
as the esoteric Mahayana school known as the Vajrayana ('The Way of the
Adamantine Thunderbolt') practiced in Tibet, and thence t he other
Himalayan countries. Buddhism was introduced into Tibet by the great
Indian yogi Padmasambhava in the eighth century, and Vajrayana is a
complex mixture of Indian transcendental philosophy and esoteric ritual
derived both from Tantric sources of north east India and Tibet's
indigenous shamanistic religion of Bon-Po. Linked to and ancient Central
Asian tradition, Bon-Po provided much of the vocabulary that expressed
the Mahayana vision, including masked spirit dances, rituals using human
bones and skull-caps, communal exorcism, liturgical music, and offerings
sculpted out of yak butter, one of the country's most treasured commodities.